Early in the pandemic, epidemiologists made a striking observation. Compared to the general population, people with cardiovascular disease (CVD) were more than twice as likely to contract severe forms of COVID-19. In the last six months, death rates from COVID-19 have dropped significantly, but CVD remains a major predictor of poor outcome. What have we learned about heart disease and COVID-19 in that time?
Pre-existing heart conditions and poor metabolic health increase risk of severe COVID-19
As I described in a blog post back in April, some health conditions, like diabetes, increase risk of severe COVID-19 by suppressing the immune system; others, like asthma, increase risk by weakening the lungs. However, in the early months of the pandemic it was not entirely clear how CVD increased the risk of severe COVID-19. We now have two explanations.
The first is that pre-existing heart conditions, such as damaged heart muscle or blocked heart arteries, weaken the body’s ability to survive the stress of the illness. A person with a vulnerable heart is more likely to succumb to the effects of fever, low oxygen levels, unstable blood pressures, and blood clotting disorders — all possible consequences of COVID-19 — than someone previously healthy.
A second explanation relates to poor underlying metabolic health, which is more common in those with heart disease. Poor metabolic health refers to diseases such as type 2 diabetes or prediabetes and obesity, which themselves cause inflammation and risk of blood clots, compounding the effects of COVID-19 and increasing the likelihood of devastating complications of COVID-19.
How does COVID-19 cause heart damage?
The SARS-CoV-2 virus can damage the heart in several ways. For example, the virus may directly invade or inflame the heart muscle, and it may indirectly harm the heart by disrupting the balance between oxygen supply and demand.